/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | foam-extend: Open Source CFD
   \\    /   O peration     | Version:     4.1
    \\  /    A nd           | Web:         http://www.foam-extend.org
     \\/     M anipulation  | For copyright notice see file Copyright
-------------------------------------------------------------------------------
License
	This file is part of foam-extend.

	foam-extend is free software: you can redistribute it and/or modify it
	under the terms of the GNU General Public License as published by the
	Free Software Foundation, either version 3 of the License, or (at your
	option) any later version.

	foam-extend is distributed in the hope that it will be useful, but
	WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with foam-extend.  If not, see <http://www.gnu.org/licenses/>.

\*---------------------------------------------------------------------------*/

#include <sys/types.h>

#include "regExp.H"
#include "foamString.H"
#include "List.H"

// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //

template<class StringType>
bool Foam::regExp::matchGrouping
(
	const std::string& str,
	List<StringType>& groups
) const
{
	if (preg_ && str.size())
	{
		size_t nmatch = ngroups() + 1;
		regmatch_t pmatch[nmatch];

		// Also verify that the entire string was matched.
		// pmatch[0] is the entire match
		// pmatch[1..] are the (...) sub-groups
		if
		(
			regexec(preg_, str.c_str(), nmatch, pmatch, 0) == 0
		 && (pmatch[0].rm_so == 0 && pmatch[0].rm_eo == label(str.size()))
		)
		{
			groups.setSize(ngroups());
			label groupI = 0;

			for (size_t matchI = 1; matchI < nmatch; matchI++)
			{
				if (pmatch[matchI].rm_so != -1 && pmatch[matchI].rm_eo != -1)
				{
					groups[groupI] = str.substr
					(
					    pmatch[matchI].rm_so,
					    pmatch[matchI].rm_eo - pmatch[matchI].rm_so
					);
				}
				else
				{
					groups[groupI].clear();
				}
				groupI++;
			}

			return true;
		}
	}

	groups.clear();
	return false;
}


// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //

Foam::regExp::regExp()
:
	preg_(0)
{}


Foam::regExp::regExp(const char* pattern, const bool ignoreCase)
:
	preg_(0)
{
	set(pattern, ignoreCase);
}


Foam::regExp::regExp(const std::string& pattern, const bool ignoreCase)
:
	preg_(0)
{
	set(pattern.c_str(), ignoreCase);
}


// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //

Foam::regExp::~regExp()
{
	clear();
}


// * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //

void Foam::regExp::set(const char* pattern, const bool ignoreCase) const
{
	clear();

	// Avoid nullptr pointer and zero-length patterns
	if (pattern && *pattern)
	{
		int cflags = REG_EXTENDED;
		if (ignoreCase)
		{
			cflags |= REG_ICASE;
		}

		const char* pat = pattern;

		// Check for embedded prefix for ignore-case
		// this is the only embedded prefix we support
		// - a simple check is sufficient
		if (!strncmp(pattern, "(?i)", 4))
		{
			cflags |= REG_ICASE;
			pat += 4;

			// avoid zero-length patterns
			if (!*pat)
			{
				return;
			}
		}

		preg_ = new regex_t;
		int err = regcomp(preg_, pat, cflags);

		if (err != 0)
		{
			char errbuf[200];
			regerror(err, preg_, errbuf, sizeof(errbuf));

			FatalErrorIn
			(
				"regExp::set(const char*, const bool ignoreCase)"
			)   << "Failed to compile regular expression '" << pattern << "'"
				<< nl << errbuf
				<< exit(FatalError);
		}
	}
}


void Foam::regExp::set(const std::string& pattern, const bool ignoreCase) const
{
	return set(pattern.c_str(), ignoreCase);
}


bool Foam::regExp::clear() const
{
	if (preg_)
	{
		regfree(preg_);
		delete preg_;
		preg_ = 0;

		return true;
	}

	return false;
}


std::string::size_type Foam::regExp::find(const std::string& str) const
{
	if (preg_ && str.size())
	{
		size_t nmatch = 1;
		regmatch_t pmatch[1];

		if (regexec(preg_, str.c_str(), nmatch, pmatch, 0) == 0)
		{
			return pmatch[0].rm_so;
		}
	}

	return string::npos;
}


bool Foam::regExp::match(const std::string& str) const
{
	if (preg_ && str.size())
	{
		size_t nmatch = 1;
		regmatch_t pmatch[1];

		// Also verify that the entire string was matched
		// pmatch[0] is the entire match
		if
		(
			regexec(preg_, str.c_str(), nmatch, pmatch, 0) == 0
		 && (pmatch[0].rm_so == 0 && pmatch[0].rm_eo == label(str.size()))
		)
		{
			return true;
		}
	}

	return false;
}


bool Foam::regExp::match
(
	const std::string& str,
	List<std::string>& groups
) const
{
	return matchGrouping(str, groups);
}


bool Foam::regExp::match
(
	const std::string& str,
	List<Foam::string>& groups
) const
{
	return matchGrouping(str, groups);
}


// * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * * //

void Foam::regExp::operator=(const char* pat)
{
	set(pat);
}


void Foam::regExp::operator=(const std::string& pat)
{
	set(pat);
}


// ************************************************************************* //
